Evaluation of different training systems on Annurca apple fruits revealed by agronomical, qualitative and NMR-based metabolomic approaches

Nine different training systems for “Annurca Rossa del Sud” apple fruits, including oblique palmette, free palmette, V-shaped, Tatura trellis, Bibaum®, modified Bibaum®, triple leader, slender spindle and Solaxe, were evaluated based on agronomic, qualitative and metabolomic traits. Fruits were analysed at harvest and after the reddening process. The slender spindle training system showed the highest cumulative efficiency yield compared to the others. Furthermore, an increase in the content of bioactive compounds in flesh and fruit peels was observed after the reddening process and was influenced by the different training systems. The metabolic variations in apple peel were measured and analysed. Changes in the metabolome highlight the influence of different training systems on apple quality. This multidisciplinary study expands our knowledge of the influence of training systems on a typical Italian apple cultivar.